Heat transfer unit extrusion process

ABSTRACT

An extrusion process for forming heat transfer units or portions thereof for use in a cooling system for cooling heat generating components in an electronic system. Several embodiments of the present invention are presented. In one embodiment, a material is extruded through a die and a housing is formed that can be used as the housing or a portion thereof, for the heat transfer unit.

CROSS REFERENCE TO RELATED APPLICATIONS

Reference is made to pending U.S. patent application Ser. No. 10/688,587 filed Oct. 18, 2003 for a detailed description of cooling systems and various heat transfer units and heat exchangers and their operation.

BACKGROUND OF THE INVENTION Description of the Related Art

At the heart of data processing and telecommunication devices are processors and other heat-generating components which are becoming increasingly more powerful and generating increasing amounts of heat. As a result, more powerful cooling systems are required to prevent these components from thermal overload and resulting system malfunctions or slowdowns.

Traditional cooling approaches such as heat sinks and heat pipes are unable to practically keep up with this growing heat problem. As these components become increasingly more powerful, the size and weight of air-cooled solutions become more problematic as well. In smaller housings or rack mounted systems, the space required for air-cooled solutions becomes unacceptable. Cooling systems which use a liquid or gas or a combination there of to cool these heat generating components are becoming increasingly needed and more viable. These systems utilize heat transfer units thermally coupled to the heat generating components for absorbing or extracting heat from the heat generating components into a coolant flowing there through. The coolant, now heated, is directed to a heat exchanger where heat is dissipated from the coolant, creating cooled coolant and returned to the heat transfer unit to repeat the cycle.

The heat transfer units typically comprise a housing with a cavity there through for the coolant to flow through. The contact surface (with the heat generating components) must have excellent thermal transfer capability and a wide variety of materials can be used such as copper.

Currently, these heat transfer units are produced by a variety of methods which are not optimal

Thus, there is a need in the art for a method to cost-effectively produce heat transfer units seamless and fast method of thermally coupling heat transfer units to heat generating components on line. There is also a need in the art for a cost-effective conduit arrangement which will retain its shape and not deter coolant flow when bent or formed to curve or angle and which will not create undesired suction effects on the coolant transport system.

SUMMARY OF THE INVENTION

A method for fabricating a portion of a heat transfer unit used for cooling heat-generating components in an electronic system comprising the step of extruding a first material to form an extruded portion of one or more heat transfer unit housings.

The method as described above further comprising the steps of adjusting the first material to a malleable state; forming the malleable first material into the shape of the extruded portion of the heat transfer unit housing; and hardening the extruded portion of the heat transfer unit housing.

The method as described above wherein the step of forming the malleable first material into the shape of the extruded portion of the heat transfer unit housing comprises inserting the malleable first material into and through a die.

The method as described above wherein the die is configured such that at least one side of the extruded portion of the heat transfer unit housing has a different thickness than the other sides.

The method as described above further comprising the additional step of adjusting the extruded portion of the heat transfer unit housing to a desired length.

The method as described above wherein the extruded portion of the heat transfer unit housing is a body having a cavity therethrough, the method further comprising the additional step of closing one or more ends of the extruded portion shortly after the extrusion exits the die and while the material is still malleable thereby resulting an enclosed cavity.

The method as described above wherein the extruded portion of the heat transfer unit housing is a body having a cavity therethrough, the method further comprising the additional step of closing one or more ends in a separate process thereby resulting an enclosed cavity.

The method as described above wherein the extruded portion of the heat transfer unit housing is a body having a cavity therethrough, the method further comprising the additional step of closing one or more ends by applying pressure to change the shape of the extrusion thereby resulting an enclosed cavity.

The method as described above wherein the extruded portion of the heat transfer unit housing is a body having a cavity therethrough, the method further comprising the additional step of closing one or more ends by applying additional material thereby resulting an enclosed cavity.

The method as described above wherein the ends are closed by attaching one or more end plates to the extruded portion of the heat transfer unit housing, the ends having an opening and means coupled to the openings for mating with a coolant pathway.

The method as described above wherein the extruded portion of the heat transfer unit housing is a partial housing with at least one open side, the method further comprising the additional steps of forming a multi-sided, second portion of the heat transfer unit housing from a second material; and attaching the second portion to the extruded portion of the heat transfer unit thereby forming an enclosed cavity.

The method as described above wherein the second portion of the heat transfer unit housing has one or more openings and means coupled to the openings for mating with a coolant pathway.

The method as described above wherein the second material is a different material than the first material.

The method as described above wherein the second portion is formed by extrusion.

The method as described above wherein the extruded portion of the heat transfer unit housing is a partial housing having an open surface and no ends, the method further comprising the additional steps of forming ends to the extruded portion of the heat transfer unit housing thereby forming a housing with an open or partially open surface.

The method as described above wherein the ends are formed by attaching one or more end plates to the extruded portion of the heat transfer unit housing, the ends having an opening and means coupled to the openings for mating with a coolant pathway.

The method as described above further comprising the additional step of attaching the heat transfer unit housing to the surface of a heat-generating component such that the open or partially open surface of the heat transfer unit is coupled to such surface of the heat-generating component, whereby, in operation, coolant circulating through the heat transfer unit can directly contact the surface of the heat-generating component to be cooled.

The method as described above further comprising the additional step of attaching a third material to the ends and the extruded portion of the heat transfer unit housing thereby eliminating the open surface of the heat transfer unit and forming a heat transfer unit with an enclosed cavity.

The method as described above wherein one or more ends have an opening and means coupled to the openings for mating with a coolant pathway.

The method as described above wherein the third material is fabricated from a different material than the first material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a cooling system.

FIG. 2A is a cross-sectional view of a die for extruding a portion of the heat transfer unit.

FIG. 2B is a three-dimensional view of the portion of the heat transfer unit extruded from the die of FIG. 2A.

FIG. 2C is a front view of an end piece to be attached to the portion of the heat transfer unit of FIG. 2B.

FIG. 3A is a cross-sectional view of another die for extruding a portion of the heat transfer unit.

FIG. 3B is a three-dimensional view of the portion of the heat transfer unit extruded from the die of FIG. 3A.

FIG. 3C is a three-dimensional view of a second portion of the heat transfer unit to be attached to the portion of the heat transfer unit of FIG. 3B.

FIG. 4A is a cross-sectional view of another die for extruding a portion of the heat transfer unit.

FIG. 4B is a three-dimensional view of the portion of the heat transfer unit extruded from the die of FIG. 3A.

FIG. 4C is a front view of an end piece to be attached to the portion of the heat transfer unit of FIG. 4B.

FIG. 5 is a three-dimensional an assembled of a heat transfer unit.

DETAILED DESCRIPTION

Whilst the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts, which can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention and do not limit the scope of the invention.

It should be understood that the principles and applications disclosed herein can be used to make heat transfer units in a wide range of data processing systems, telecommunication systems and other systems such as electrical and electronic systems.

The present invention may be utilized to make heat transfer units for a number of computing, communications, and personal convenience applications. For example, the heat transfer units made with the present invention could be implemented in a variety of servers, workstations, exchanges, networks, controllers, digital switches, routers, personal computers which are portable or stationary, optical, data processing units, cell phones, and personal digital assistants (PDAs) and many others.

Heat transfer units made with the present invention are equally applicable to a number of heat-generating components (e.g., central processing units, optical devices, data storage devices, digital signal processors or any component that generates significant heat in operation) within such systems. Furthermore, the dissipation of heat in this cooling system may be accomplished in any number of ways by a heat exchange unit of various designs, but which are not discussed in detail in this application.

Referring now to FIG. 1, a schematic diagram of a cooling system 100 is depicted. A heat-generating component 101 such as, but not limited to, a micro-processor, to be cooled is thermally coupled to a heat transfer unit 102. The heat transfer unit is depicted with an outlet 103 and an inlet 104. A coolant pathway 108A/108B connects the outlet 103 of the heat transfer unit 102 to the inlet 106 of a heat exchange unit or dissipater 105. A coolant pathway 109A/109B connects the outlet 107 of the heat exchange unit 105 to the inlet 104 of a heat transfer unit 102.

In operation, the coolant follows the directional arrows depicted. Cooled coolant enters the inlet 104 of the heat transfer unit 102. Heat from the heat generating component 101 is transferred to the coolant thereby creating heated coolant and cooling the heat generating component. The heated coolant exits the heat transfer unit through outlet 103 and then, via coolant pathway 108A/108B enters the heat exchange unit 105 through inlet 106. The heat exchange unit dissipates heat from the coolant thereby creating cooled coolant which exits the heat exchange unit through outlet 107 and is returned to the heat transfer unit via coolant pathway 109A/109B. This cycle is continuously repeated. The coolant in the system 100 may be water or a mixture such as, for example, a propylene glycol based coolant or a gas.

In FIG. 1, the outlet 103 of the heat transfer unit 102 and the inlet 106 of the heat exchange unit 105 are depicted as being above the inlet 104 and the outlet 107, respectively. Whenever possible, the arrangement should be chosen to let convective circulation assist with the circulation of the coolant through the system.

It will be appreciated that coolant pathways 108A/108B and 109A/109B may be a single conduit or a combination of components as shown and connected with connectors as required. It will also be appreciated that the heat exchange unit 105 may be one of a variety of types of heat exchange units such as those discussed in cross-referenced pending U.S. patent application Ser. No. 10/688,587.

In FIG. 1, the heat transfer unit 102 is depicted as a rectangular housing with a hollow cavity there through. One surface of the heat transfer unit is thermally coupled to the heat generating component 101. It will be appreciated that the present invention is not limited to heat transfer units of rectangular shape and that other shapes may be used. The only limitation on the shape of the heat transfer unit 102 is that it should cover the surface of the heat generating component 101 to which it is thermally coupled and be of a shape and contour that will facilitate a good thermal coupling with the surface of the heat generating component 101.

In FIG. 5, a complete heat transfer unit 501 made using the present invention is depicted. It will be understood that the heat transfer unit 501, including the inlet 502 and the outlet 503, is the result when the process described in FIGS. 2A, 2B and 2C, or FIGS. 3A, 3B and 3C or FIGS. 4A, 4B and 4C is used.

In FIG. 2A, a cross-sectional view of a die 201 for forming a portion of the heat transfer unit 202 in FIG. 2B housing is depicted. The die 201 is shaped such that, when a malleable material is inserted into and through the die 201 (or forced through the die 201), a rectangular shaped casing will result when it exits the die 201. It will be appreciated and any shape for the housing can be selected merely by forming the die correspondingly. To fabricate the housing for the heat transfer unit 202, a material such as copper, brass, aluminum or a variety of other materials is heated or adjusted to the point of malleability. It is preferable to adjust the material so that it is malleable, but not liquid, and can be easily extruded through the die 201 and still retain the desired shape after exiting the die 201. Materials not requiring heat malleability can also be used in this process, including, but not limited to, epoxies, composites, plastics, phenol formaldehyde or a wide variety of other materials and/or any combination of these materials. Malleable and non-malleable materials may be combined in the extrusion process or after the extrusion process.

In FIG. 2B, the resulting housing for the heat transfer unit 202 after being formed by the die is depicted. When the material exits the die 201, it is cooled or allowed to cool to or otherwise hardened After hardening, the housing is cut or otherwise adjusted or altered to the desired length to appropriately couple to the heat generating component that it eventually will be used to cool. As will be obvious to anyone skilled in the art, it is preferable, but not necessary, to have the length of the housing exiting the die be such that many housings for heat transfer units 202 can be cut from it. The resulting housing for the portion of heat transfer unit 202, in the example depicted in FIG. 2B, then will be rectangular in shape with no end pieces.

The die 201 in FIG. 2A is depicted such that the thickness of each side of the resulting portion of the heat transfer unit 202 is the same. It will be appreciated, however, that this is not a requirement and that the thicknesses of each side may vary. In fact, it may be preferable to form the die such that one side of the resulting portion of the housing for the heat transfer unit 202 is substantially thinner or thicker than the others. The resulting side of the heat transfer unit housing 202 would then be used as the side which is thermally coupled to the heat generating component. This is preferable because the ability to vary the thickness allows the head transfer unit to produce different results to suite a wide variety of applications.

Referring now to FIG. 2C, a side view of an end plate 203 for the housing 202 is depicted. The end plate 203 is depicted with an opening and coupling mechanism 204. An end plate 203 is fastened to both open ends of the portion of the heat transfer unit 202 by welding or any number of suitable methods to form the complete heat transfer unit 501 as shown in FIG. 5. The end plates may be made from any suitable material and need not be the same material as used the extruded portion of the heat transfer unit 202. A hole may be cut or drilled into the end plate and a coupling mechanism assembled thereto to form a device for coupling with the coolant pathway. When the complete heat transfer unit 501 is assembled, it has an appropriate inlet 502 and outlet 503.

It will be further appreciated that the two hole and coupling assemblies 204 may be disposed on the portion of the heat transfer unit 202 instead of on the end plate(s) 203. Moreover, it will be appreciated that other methods of forming the end plate(s) 203 or in lieu of the end plates may be utilized within the scope of the present invention. For example, the housing 202 could be made oversized enough so that the open ends could be crimped or otherwise forced together to form an enclosed housing. Alternatively, the housing could be machined at both open ends to create flaps that can be folded over and sealed together to form a sealed, enclosed housing. The open ends could also be sealed with a wide variety of other materials such as, but not limited to, epoxies, polymers, or other suitable materials. It should also be appreciated that any combination of these methods can be utilized to close the extrusion. The open ends may also be closed with tubes or conduits inserted in the opening, the opening could be sealed by any of the methods previously mentioned.

In FIG. 3A, a cross-sectional view of a die 301 for forming a portion of the heat transfer unit 302 in FIG. 3B housing is depicted. This die 301 is similar to the die 201 in FIG. 2A except that the resulting portion of the heat transfer unit 302 only has 3 sides. It will be appreciated that any shape for the housing can be selected merely by forming the die correspondingly. For example, the die 301 could be formed such that the shape of the housing 302 is a half-cylinder as long as the other portion of the heat transfer unit 303 is formed to assemble or mate with it. The portion of the heat transfer unit 302 is then formed in the same manner as that described for FIGS. 2A and 2B.

In FIG. 3C, the mating piece 303 for the portion of the heat transfer unit 302 depicted in FIG. 3B, is depicted. The mating piece 303 may be formed from a sheet of any suitable material that is bent, for example, along the lines shown at 306 and 307 to form a mating piece for the portion of the heat transfer unit 302. It will be appreciated that other means may be employed to fabricate piece 303 including the extrusion process of the present invention. For example, a die similar to die 301 may be made to produce in one step the mating piece 303. This die may also be constructed such that the three sides of the resulting mating piece 303 have different thicknesses as desired.

One advantage of the process described for FIGS. 3A, 3B and 3C to construct the heat transfer unit 501 over the process described for FIGS. 2A, 2B and 2C occurs when it is desirable to use different materials in the heat transfer unit 501. For example, it may be desirable, for certain applications, to fabricate the side of the heat transfer unit 501 that will be thermally coupled to the heat generating component out of a more expensive, higher coefficient of heat transfer, material (e.g. copper) than the material (e.g. brass or aluminum) used for other parts of the heat transfer unit 501.

It will also be appreciated that the hole and mating assemblies 304 and 305 may be disposed on the portion of the heat transfer unit housing 302 instead of mating piece 303.

In FIG. 4A, a cross-sectional view of a die 401 for forming a portion of the heat transfer unit 402 in FIG. 4B housing is depicted. This die 401 is similar to the die 301 in FIG. 3A. Also, the resulting portion of heat transfer unit 402 is similar to the resulting porting of the heat transfer unit 302. It will be appreciated that any shape for the housing can be selected merely by forming the die correspondingly. For example, the die 401 could be formed such that the shape of the housing 402 is a half-cylinder as long as the end plate(s) 403 is/are formed to be assembled or mated with it. The portion of the heat transfer unit 402 is then formed in the same manner as that described for FIGS. 3A and 3B.

Referring now to FIG. 4C, a side view of an end plate 403 for the housing 402 is depicted. The end plate 403 is similar to the end plate 203 in FIG. 2C and is fastened or secured to the housing 402 in a similar manner as that described above.

When housing 402 and two end plates 403 are fastened together, a heat transfer unit 501 is formed which has an open surface. When thermally coupling this heat transfer unit to a heat generating component, the open surface of the heat transfer unit must be sized to create a tight seal with the surface of the heat generating component so that coolant cannot leak or escape. An advantage of such a heat transfer unit is that it allows direct contact of the coolant with the surface of the heat generating component. This eliminates the thermal resistance of the contact surface of the heat transfer unit 502 thus improving the coefficient of heat transfer.

Thus, the present invention has been described herein with reference to particular embodiments for particular applications. Those having ordinary skill in the art and access to the present teachings will recognize additional modifications, applications, and embodiments within the scope thereof.

It is, therefore, intended by the appended claims to cover any and all such applications, modifications, and embodiments within the scope of the present invention. 

1. A method for fabricating a portion of a heat transfer unit used for cooling heat-generating components in an electronic system, the method comprising the step of: extruding a first material to form an extruded portion of one or more heat transfer unit housings.
 2. The method as set forth in claim 1 wherein the step of extruding the first material comprises the steps of: adjusting the first material to a malleable state; forming the malleable first material into the shape of the extruded portion of the heat transfer unit housing; and hardening the extruded portion of the heat transfer unit housing.
 3. The method as set forth in claim 2 wherein the step of forming the malleable first material into the shape of the extruded portion of the heat transfer unit housing comprises: inserting the malleable first material into and through a die.
 4. The method as set forth in claim 3 wherein the die is configured such that at least one side of the extruded portion of the heat transfer unit housing has a different thickness than the other sides.
 5. The method as set forth in claim 2 comprising the additional step of: adjusting the extruded portion of the heat transfer unit housing to a desired length.
 6. The method as set forth in claim 2 wherein the extruded portion of the heat transfer unit housing is a body having a cavity therethrough, the method comprising the additional step of: closing one or more ends of the extruded portion shortly after the extrusion exits the die and while the material is still malleable thereby resulting an enclosed cavity.
 7. The method as set forth in claim 2 wherein the extruded portion of the heat transfer unit housing is a body having a cavity therethrough, the method comprising the additional step of: closing one or more ends in a separate process thereby resulting an enclosed cavity.
 8. The method as set forth in claim 2 wherein the extruded portion of the heat transfer unit housing is a body having a cavity therethrough, the method comprising the additional step of: closing one or more ends by applying pressure to change the shape of the extrusion thereby resulting an enclosed cavity.
 9. The method as set forth in claim 2 wherein the extruded portion of the heat transfer unit housing is a body having a cavity therethrough, the method comprising the additional step of: closing one or more ends by applying additional material thereby resulting an enclosed cavity.
 10. The method as set forth in claim 9 wherein the ends are closed by attaching one or more end plates to the extruded portion of the heat transfer unit housing, the ends having an opening and means coupled to the openings for mating with a coolant pathway.
 11. The method as set forth in claim 2 wherein the extruded portion of the heat transfer unit housing is a partial housing with at least one open side, the method comprising the additional steps of: forming a multi-sided, second portion of the heat transfer unit housing from a second material; and attaching the second portion to the extruded portion of the heat transfer unit thereby forming an enclosed cavity.
 12. The method as set forth in claim 11 wherein the second portion of the heat transfer unit housing has one or more openings and means coupled to the openings for mating with a coolant pathway.
 13. The method as set forth in claim 11 wherein the second material is a different material than the first material.
 14. The method as set forth in claim 11 wherein the second portion is formed by extrusion.
 15. The method as set forth in claim 2 wherein the extruded portion of the heat transfer unit housing is a partial housing having an open surface and no ends, the method comprising the additional steps of forming ends to the extruded portion of the heat transfer unit housing thereby forming a housing with an open or partially open surface.
 16. The method as set forth in claim 15 wherein the ends are formed by attaching one or more end plates to the extruded portion of the heat transfer unit housing, the ends having an opening and means coupled to the openings for mating with a coolant pathway.
 17. The method as set forth in claim 15 comprising the additional step of: attaching the heat transfer unit housing to the surface of a heat-generating component such that the open or partially open surface of the heat transfer unit is coupled to such surface of the heat-generating component, whereby, in operation, coolant circulating through the heat transfer unit can directly contact the surface of the heat-generating component to be cooled.
 18. The method as set forth in claim 15 comprising the additional step of: attaching a third material to the ends and the extruded portion of the heat transfer unit housing thereby eliminating the open surface of the heat transfer unit and forming a heat transfer unit with an enclosed cavity.
 19. The method as set forth in claim 18 wherein one or more ends have an opening and means coupled to the openings for mating with a coolant pathway.
 20. The method as set forth in claim 18 wherein the third material is fabricated from a different material than the first material. 